Carbonyl Compounds Flashcards
what functional group do aldehydes and ketones contain?
Carbonyl functional group
O
II
R-C-R
The part of the molecule which takes part in chemical reactions
where is the carbonyl group in aldehydes?
they have the carbonyl group on a carbon with at least one hydrogen atoms attached to it
where is the carbonyl group on a ketone?
attached to 2 alkyl groups
What are primary alcohols oxidised to?
aldehydes
what are secondary alcohols oxidised to?
ketones
what do the oxidation reactions of secondary and primary alcohols produce?
water
why can’t hydrochloric acid not be used with a powerful oxidising agent?
because the chloride ion could be oxidised
what are phenols resistant to?
oxidation under normal conditions
what can the aldehydes and ketones be reduced by and what is it normally done in?
Using sodium borohydride (NaBH4) normally this is done in aqueous solution or ethanol at room temperature
what are the reduction products when aldehydes and ketones are reduced by sodium borohydride?
The corresponding alcohols
what do aldehydes and ketones produce when they are reduced by sodium borohydride?
-Aldehydes produce primary alcohols
-Ketones produce secondary alcohols
How can we show the reduction of ethanol?
using [H] as the reducing agent
what is the carbonyl group in the aldehyde and ketone and what does this do?
polar which makes the carbon atom electron deficient and suspectible to attack by nucleophiles
Why is the carbonyl group of an aldehyde and ketone unsaturated?
as it contains a carbon to oxygen double bond and it undergoes nucleophilic addition reaction to provide the one product; an alcohol.
The sodium borohydride generates the hydride (H) ion in solution.
sodium ion is a spectator and is never included in reaction mechanisms or equations.
what does the reduction in the nucleophilic addition of hydride take place by?
the addition of the hydride ion across the carbonyl group followed by the protonation, by H+ or by water, of the intermediate organic species produced
what does nucleophilic addition produce?
one product
what does hydrogen cyanide produce and what can this do?
-the nucleophilic cyanide ion -CN, which can aso attack the carbonyl carbon of an aldehyde or ketone.
-The product is called a hydroxy nitrile (you may also see the name cyanohydrin).
What can nitrites be reduced by and what does this produce?
using nickel and hydrogen to produce the corresponding amine
What happens when a solution of 2,4-dinitrophenylhydrazine(Brady’s reagent) is added to an aldehyde or a ketone?
a deep yellow or orange solid is made
What are aldehydes easily oxidised to and what by but what can ketones not do?
mild oxidising agents whereas ketones are cannot be oxidised further.
what is Tollens’ reagent (ammoniacal silver nitrate)?
a weak oxidising agent, which can be used to distinguish between the aldehyde and the ketone.
What happens when you add tollens’ reagent to an aldehyde and a ketone?
-Aldehyde- silver mirror is formed
-Ketone- No reaction
what is the oxidising species in tollens’ reagent?
The aqueous silver (I) ions, Ag+ (aq)
What happens when tollens’ reagent reacts with the aldehyde?
the aldehyde is oxidised to a carboxylic acid and the silver ions are reduced to silver metal
is water produced when an aldehyde oxidised?
no
